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[Change]: [1.93] Stabilize ABI of C-style variadic function declarations #654

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Merged
tshepang merged 1 commit into from
Feb 5, 2026
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[Change]: [1.93] Stabilize ABI of C-style variadic function declarations #654

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3 changes: 3 additions & 0 deletions src/changelog.rst
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Original file line number Diff line number Diff line change
Expand Up @@ -27,6 +27,9 @@ Language changes in Rust 1.93.0
- No change: the target is outside the scope of FLS

- `Stabilize declaration of C-style variadic functions for the system ABI <https://github.com/rust-lang/rust/pull/145954>`_

- Changed paragraph: :p:`fls_8m7pc3riokst`

- `Emit error when using some keyword as a cfg predicate <https://github.com/rust-lang/rust/pull/146978>`_

- No change: this bug was not documented in FLS
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8 changes: 4 additions & 4 deletions src/ffi.rst
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Expand Up @@ -74,7 +74,7 @@ The following :t:`[ABI]s` are supported:
:dt:`Rust ABI`.

* :dp:`fls_8m7pc3riokst`
``extern "system"`` - The operating system-dependent :t:`ABI`.
``extern "system"`` - The operating system-dependent :t:`ABI`. This :t:`ABI kind` is equivalent to ``extern "C"`` except on Windows x86_32 where it is equivalent to ``extern "stdcall"`` for non-:t:`[variadic function]s`, and equivalent to ``extern "C"`` for :t:`[variadic function]s`.

* :dp:`fls_NQAzj5ai1La5`
``extern "system-unwind"`` - The same as ``extern "system"`` with the
Expand Down Expand Up @@ -108,6 +108,9 @@ include, but may not be limited to, the following:
``extern "cdecl-unwind"`` - The same as ``extern "cdecl"``
with the addition that unwinding across FFI is permitted.

* :dp:`fls_JHlqXjn4Sf07`
``extern "efiapi"`` - The :t:`ABI` for `UEFI <https://uefi.org/specifications>`_.

* :dp:`fls_6rtj6rwqxojh`
``extern "fastcall"`` - The ``fastcall`` :t:`ABI` that corresponds to MSVC's
``__fastcall`` and GCC and clang's ``__attribute__((fastcall))``.
Expand All @@ -133,9 +136,6 @@ include, but may not be limited to, the following:
``extern "win64-unwind"`` - The same as ``extern "win64"``
with the addition that unwinding across FFI is permitted.

* :dp:`fls_JHlqXjn4Sf07`
``extern "efiapi"`` - The :t:`ABI` for `UEFI <https://uefi.org/specifications>`_.

.. rubric:: Undefined Behavior

:dp:`fls_M4LqHf8hbPA8`
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